Push rod arrangement for turbine system

ABSTRACT

A turbine system with a push rod arrangement is presented. The turbine system includes a first turbine having a first rotor, a second turbine having a second rotor, a push rod coupled to a casing of the first turbine at a first end and to a casing of the second turbine at a second end wherein the push rod includes a device for controlling temperature.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US National Stage of International Application No. PCT/EP2012/062058 filed Jun. 22, 2012, and claims the benefit thereof. The International Application claims the benefit of European Application No. EP11176302 filed Aug. 2, 2011. All of the applications are incorporated by reference herein in their entirety.

FIELD OF INVENTION

The present invention relates to a turbine system for power generation system and more particularly to a push rod arrangement for the turbine system for use in a power generation system.

BACKGROUND OF INVENTION

A power generation system includes a turbine system such as a steam turbine system which utilizes a condenser to condense exhausted steam produced in a boiler to drive the turbine system; this steam is turned into liquid water for recirculation through the system. The turbine system includes a high pressure turbine, an intermediate pressure turbine and a low pressure turbine. A generator is coupled to the low pressure turbine via a drive shaft to generate electricity.

During operation of the power generation system, the turbine system is heated up. The casing and rotor of the turbine is generally made of different material and expand differentially. More particularly, the thermal expansion of the rotor is greater than the casing of the turbine; therefore in a turbine system thermal expansion of the intermediate pressure turbine rotor is transferred to the low pressure turbine rotor. To compensate for the expansion between the casing of the turbines and the rotors, push rods are used between the casings of the intermediate pressure turbine and the low pressure turbine.

However, there is still some differential expansion which can not be compensated through the use of current push rod mechanism resulting in accumulation of expansion at the end of the turbine system, requiring significant amount of axial clearance in the design of the turbine system.

Currently used push rods are rigid which do not allow reduction of differential expansion in rotor trains with two or three low pressure turbine configuration.

SUMMARY OF INVENTION

It is therefore an object of the present invention to provide a push rod arrangement to compensate the differential expansion between the rotor train and the casing for a turbo-machine.

This object is achieved by providing a turbine system and a power generation system as described herein.

The turbine system includes a first turbine having a first rotor, a second turbine having a second rotor, a push rod coupled to a casing of the first turbine at a first end and to a casing of the second turbine at a second end characterized in that the push rod comprises a device for controlling temperature. By having a device for controlling the temperature of the push rod, the push rod would be expanded when heated and contracted when cooled thereby compensating for differential expansion in the turbine system, wherein a steam jacket is used to heat the push rod. Steam is passed into the jacket at about 300 degree centigrade resulting in heating of the rod and resulting thermal expansion.

In one embodiment, an electrical component is used for controlling the temperature and thereby the heating the push rod. An electric current is passed to the push rod thereby causing induction heating of the rod, which results in expansion of the push rod.

According to one embodiment, the push rod includes means for cooling to allow contraction of the push rod and also control the expansion of the push rod.

In one embodiment, the means for cooling is a through hole in the push rod; the through hole in the push rod allows coolant to pass through the push rod thereby allowing cooling.

In another embodiment, the coolant includes oil or steam from low pressure turbine exhaust steam. Oil is efficient absorber of heat; also steam from low pressure turbine exhaust is at a relatively low temperature and would allow cooling of the push rod.

In one embodiment, one or more valves allow a desired amount of coolant to pass through the through hole of the push rod depending on the amount of expansion or contraction required in the push rod.

In one embodiment, the turbine system includes a measuring device for calculating the differential expansion of the push rod.

In another embodiment, the measuring device is configured to provide a signal to the temperature controlling device. The measuring device based on the differential expansion provides a signal to the temperature control device which then heats or cools the push rod.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features of the invention will now be addressed with reference to the accompanying drawings of the present invention. The illustrated embodiments are intended to illustrate, but not limit the invention. The drawings contain the following figures, in which like numbers refer to like parts, throughout the description and drawings.

FIG. 1 is a schematic diagram of a power generation system;

FIG. 2 is a schematic diagram of a turbine train;

FIG. 3 is a schematic diagram of a turbine with a temperature controlled push rod;

FIG. 4 is a schematic diagram depicting the induction heating of push rod, and

FIG. 5 is a schematic diagram of a turbine with push rod having a steam jacket arrangement.

DETAILED DESCRIPTION OF INVENTION

FIG. 1 illustrates a schematic diagram of a power generation system 1 in accordance with aspects of the present technique. The power generation system 1 includes a turbine system 2 or a turbine train including one or more turbines. The power generation system further includes a condenser assembly 4, a feed pump 8 connected to the condenser assembly 4, a boiler 10, a heat source assembly 12 and a generator 6 coupled to the turbine system 2.

The heat source assembly 12 such as a burner may include any heat source such as, but not limited to a nuclear heat source or a fossil fuel heat source which enables the power generation system 1 to function. The boiler 10 is coupled to the heat source which is also in a flow communication with the turbine system 2.

The turbine system 2, which may also be referred to as the turbine train may include one or more turbines in a serial flow arrangement such as a high pressure turbine, an intermediate pressure turbine and a low pressure turbine. The one or more turbines are coupled in flow communication with each other. The turbine system 2 is coupled in flow communication with the condenser assembly 4 and operatively coupled to the generator 6 via at least one drive shaft. The condenser assembly 4 is in flow communication with the boiler 10, a feed pump 8 facilitates pumping of condensate from condenser assembly 4 to the boiler 10. The heat source assembly 12 heats a working fluid, such as water in the boiler 10 to produce steam therein. The steam is directed into the turbine system 2 for driving the turbines, which in turn actuate the generator 6 to produce electricity.

FIG. 2 is a diagrammatical illustration of a turbine system, such as the turbine system 2 of FIG. 1. In the presently contemplated configuration, the turbine system 2 includes a high pressure turbine 20, a first turbine 22 which is an intermediate pressure turbine, a second turbine 24 and a third turbine 26. The second turbine 24 and the third turbine 26 are two low pressure turbines. The turbines are arranged in flow communication with each other. More particularly, the turbines are in a serial flow arrangement, wherein rotors of the turbines are operatively coupled to each other.

In accordance with the aspects of the present technique, the first turbine 22 includes a first rotor 28 operatively coupled to a second rotor 32 of the second turbine 24. The second rotor 32 is coupled to a third rotor 34 of the third turbine 26 as depicted in FIG. 2.

Additionally, the third rotor 34 of the third turbine 26 is coupled to the generator 6 via a drive shaft 29. The turbine system 2 also includes a high pressure turbine 20 disposed axially upstream the first turbine 22. The high pressure turbine 20 and the first turbine 22 are coupled to each other through a coupling. In one embodiment, the coupling may in-elude a thrust bearing 30 which is disposed between the first rotor 28 of the first turbine 22 and a rotor of the high pressure turbine 20. The thrust bearing 30 prevents expansion of the first rotor 28 in a direction towards the high pressure turbine 20. More particularly, the thrust bearing 30 is disposed at a second face (not shown in FIG. 2) of the first rotor 28.

In accordance with aspects of the present technique, the turbine system includes a measuring device 40 such as a differential expansion (DE) meter coupled to the third turbine 26. More particularly, in the presently contemplated configuration, the DE meter is placed at a location proximal to the generator 6. It may be noted that the DE meter is connected to an inner casing of the third turbine 26. The DE motor is configured to provide a signal as an output to a temperature controlling device of a push rod (not shown in FIG. 2).

However, in other embodiments, one or more DE meters may be present wherein each DE meter is coupled to each turbine to measure the differential expansion at each turbine.

The temperature controlling device may be a heating system for the push rod. It may be noted that heating in the push rod may be induced electrically, such as, by passing an electric current to heat the push rod. Alternatively, heating in the push rod may be produced by passing heated substance such as a steam flow to increase the temperature of the push rod as will be described with reference to FIG. 3 and FIG. 4.

FIG. 3 is a schematic diagram depicting a section of a turbine 50 in accordance with aspects of the present technique. A push rod 54 is coupled to an inner casing 56 of the steam turbine 50 at a first end and to an outer casing 58 of the second turbine (not shown) at the second end. The push rod 54 includes a device 52 for controlling temperature. The device 52 is an electric component such as an electric current regulator for passing a desired amount of current to the push rod 54. The current when passed through the push rod via an inductor heats the push rod thus raising the temperature of the push rod 54.

In the presently contemplated configuration, the push rod 54 includes means for cooling such as but not limited to a through hole 60 which is used for cooling purposes. The through hole 60 extends along the length of the push rod 54. The through hole 60 allows a coolant to pass through it thereby reducing the temperature of the push rod 54.

In accordance with aspects of the present technique, the coolant may include material such as oil. Alternatively, steam from the low pressure turbine exhaust steam may be used as a coolant.

In one embodiment, an oil spray system may also be used as a means for cooling the push rod.

The push rod 54 is heated to a temperature of about 300 degree centigrade which results in the expansion of push rod in the range of about 8 to 9 mm. In case, a lesser expansion is needed the cooling mechanism as described hereinabove may be used. It may be noted that the flow of coolant in the through hole 60 may be controlled through a use of valves (not shown in FIG. 3). The measuring device 40 which is the DE meter measures the differential expansion between the casing and the rotor of the turbine system. The DE meter 40 provides a signal to the device 52 for controlling temperature which is the electric current regulator to provide a desired current to heat the push rod 54 accordingly.

FIG. 4 is a schematic diagram depicting the exemplary push rod arrangement in accordance with aspects of the present technique. The push rod 54 is coupled to an inner casing to the first turbine 22 at a first end 66 and to the outer casing of the second turbine 24 at a second end 68. The temperature controlling device 52, which is an electric current regulator provides a desired amount of current to heat the push rod 54, as illustrated in FIG. 4. As previously noted the push rod 54 includes the through hole 60 for allowing the coolant to pass through the push rod 54 for cooling purposes. One or more valves 64 control a flow 62 of the coolant based on the desired amount of cooling required for the push rod 54.

Referring to FIG. 5, a schematic diagram depicting a section of a turbine 70 is depicted. The turbine 70 includes a push rod 54 with a device for controlling temperature. In the presently contemplated configuration the device is a steam jacket 72 enclosing the push rod 54. Steam from the first turbine, such as, the intermediate pressure turbine is used to heat the push rod 54. Steam from the intermediate pressure turbine is at a temperature of around 350 degree centigrade; such temperature is capable of heating the push rod 54 and causing thermal expansion in the push rod 54.

As previously mentioned, the push rod 54 includes the through hole 60 for passing coolant for controlled contraction of the push rod 54. The measuring device 40, such as DE meter is connected to the steam jacket 72 which provides information on the extent of expansion required in the push rod to compensate for the differential expansion between the rotor and the casing of the turbines in the turbine system. A steam mass flow may be regulated based on the information from the measuring device 40.

Although, the embodiments of the present invention have been described with respect to a turbine system, such as a steam turbine system, it may be noted that similar technique and arrangement may also be used for a gas turbine system. Particularly, the embodiments described hereinabove are applicable for steam turbine system as well as the gas turbine system. 

1. A turbine system comprising: a first turbine having a first rotor, a second turbine having a second rotor, a push rod coupled to a casing of the first turbine at a first end and to a casing of the second turbine at a second end, wherein the push rod comprises a device for controlling temperature, wherein the device comprises a steam jacket for heating the push rod.
 2. The turbine system according to claim 1, wherein the device comprises an electrical component for heating the push rod.
 3. The turbine system according to claim 1, wherein the push rod comprises means for cooling.
 4. The turbine system according to claim 3, wherein the means of cooling comprises a through hole within the push rod.
 5. The turbine system according to claim 4, wherein a coolant is passed through the through hole for cooling.
 6. The turbine system according to claim 5, wherein the coolant comprises oil or steam.
 7. The turbine system according to claim 4, further comprising one or more valves for controlling the flow of coolant in the through hole.
 8. The turbine system according to claim 1, further comprising a third turbine having a third rotor operatively coupled to the second rotor or the first rotor.
 9. The turbine system according to claim 1, further comprising a measuring device for measuring the differential expansion in the turbine system.
 10. The turbine system according to claim 9, wherein the measuring device is configured to provide a signal to the temperature controlling device.
 11. The turbine system according to claim 1, wherein the measuring device is coupled to the third rotor distal to the second rotor or the first rotor.
 12. The turbine system according to claim 1, further comprising a high pressure turbine disposed axially upstream the first turbine.
 13. A power generation system comprising a turbine system according to claim
 1. 14. The power generation system according to claim 13, wherein the device for controlling temperature comprises an electrical component for heating the push rod.
 15. The power generation system according to claim 13, wherein the device for controlling temperature comprises a steam jacket for heating the push rod. 